// 变量计算
.container {
    width: 100%;
}

article[role="main"] {
    float: left;
    width: 600px / 960px * 100%;
}

aside[role="complementary"] {
    float: right;
    width: 300px / 960px * 100%;
}


// 数学运算
.box {
    width: ((220px + 720px) - 11 * 20) / 12;
}

// 颜色运算
p {
    color: #010203 + #040506;
}

// 字符运算  #{}
$content: "Hello"+""+"Sass!";

.box:before {
    content: " #{$content} ";
}

p:before {
    content: "Foo "+ Bar;
    font-family: sans- + "serif";
}